3,5-diamino-1,2,4-triazole(DATA) was used as a diamine to introduce triazole in the backbone of polyimides. The mol% of DATA in the diamines was varied and the effects of triazole content on the mechanical properties, thermal properties and adhesion strength between polyimides and copper were investigated. Polyisoimides were also synthesized to prevent the copper diffusion into polyimide layer observed in poly(amic acid) precursors. The properties of polyimides prepared via polyisoimide including the adhesion strength to copper were examined. The locus of failure of polyimide/Cu joints was analyzed by XPS. The mechanical properties of BOD-PI did not vary with increasing the DATA content from 0 mol% to 20 mol% in diamines but the adhesion strength of BOD-PI/Cu joints increased with increasing the DATA content.